Telephone service providers that purchase telephone switching equipment prefer to be able to offer unique telephone services beyond simple telephone call routing. Unique services such as reverse charge (freephone) services, originating call screening, terminating call screening, and short-code numbering plans are just a few examples of premium services that a service provider can offer its subscribers in order to differentiate its services from those of its competitors.
One method of allowing telephone service providers to more easily customize their switching equipment to permit these premium services is through intelligent networks. Intelligent networks have existed since at least the mid-1980""s. Traditionally, these intelligent networks are invoked when a user places a call to a special number (such as an xe2x80x9c800 xe2x80x9d number in the U.S.). Dialing the number causes a trigger to be sent to the switching system causing it to communicate with an intelligent network system to find out from the intelligent network how the call is to be handled. The intelligent network provides specialized instructions to the switching system depending on the subscription services being provided to the user (or the recipient caller).
The principal advantage of intelligent networks is the flexibility to provide premium services, without having to adjust the xe2x80x9chard-codedxe2x80x9d switching system. That is, by informing the switching system that it can rely on another subsystem to direct it in performing its switching obligations when premium services are requested, the switching system itself need not have the xe2x80x9cintelligencexe2x80x9d to determine how to handle premium service switching. That intelligence resides instead in the intelligent network system, which can be modified, reprogrammed, etc. without affecting the standard switching performance of the switching system. If a standard point-to-point call is requested, the intelligent network is not invoked and the switching system can route the call in a traditional manner.
The intelligent network is made up of building blocks, called Service Independent Building blocks (SIBs). Each SIB performs a particular logic function on single input signal. A list of example SIBs in current use is shown in Appendix A. For example, one SIB may determine whether a call is received before or after a particular date. If the SIB determines it is before, the logic analysis may proceed to another SIB for further logic processing. If after, the logic may proceed to an information signal informing the switching system to terminate the call. This is just one example that illustrates how SIBs can be used to develop more sophisticated call routing instructions. The SIBs can be changed, modified, combined in number, or reduced in number to create an overall service logic for a particular premium service offered by the intelligent network.
The intelligent network with the SIB constructions provide high flexibility in offering customized services (by adding to or modifying the service logic routines) and allows changes and additions to premium services to be added quickly and inexpensively, without affecting the standard hard-coded switching system.
The use of SIBs as building blocks to create larger logic schemes is referred to as flexible logic since the overall logic desired can be built flexibly from the various SIB parts. Alternatively, service logic can be created in fixed logic, meaning that once programmed, the program is not changed by changing modular code blocks, but by changing the source code itself.
FIG. 1 illustrates a prior art service network with intelligent network capabilities. In the example of FIG. 1, a subscriber 10 has requested a premium service from its telephone service provider to permit it to receive reverse-charge calls to its sales organization and to distribute those calls evenly to the destination phone numbers of its current sales representatives. The premium service is invoked by an assigned xe2x80x9c800 xe2x80x9d number, which a caller 12 can dial. The 800 number is received by the local exchange 11.
The local exchange 11 directs the call from the caller 12 to a service switching function (SSF), which switches the call through to its destination. Before doing that, the service switching function detects triggers in the call information from the local exchange. Intelligent network calls, such as the 800 number dialed by the caller 12, will trigger the service switching function to send a message to the service control function. The service switching function (SSF) is located at a service switch point (SSP) while the service control function (SCF) is located at the service control point (SCP). Alternatively, the service switching function and the service control function may be located at the same node (then referred to as a service switching control point (SSCP)).
Generally, the service switching function sends a message to the service control function containing the dialed number from the caller 12 and general call information. This invokes a service script interpreter in the SCF, which analyzes the message received. This analysis includes finding a program behind the service and charging the service fee to the subscriber 10. After analyzing the call information in accordance with the service logic associated with the dialed number (for the subscriber 10), the SCF will inform the SSF of appropriate call switching instructions. In the example of FIG. 1, for example, the SCF may analyze the prior distribution of incoming phone calls to the subscriber 10 and route the call from caller 12 to a sales representative in the subscriber 10 in accordance with an even distribution program.
After determining the call destination, the SCF sends instructions to the SSF for switching the caller 12 to the appropriate destination at the subscriber 10. This is done in traditional fashion through transit exchange (TR) 16, possibly other service switching points 15, other transit exchanges 17, and other local exchanges 18.
As can be seen from the example of FIG. 1, an advantage of the intelligent networking is that the service switching function (SSF) of the service switching point 13 need not be coded to switch calls from caller 12 to the subscriber 10, but can instead rely upon service control functions of service control point 14 to provide that information to it. Thus, if the subscriber services for the subscriber 10 change, the service switching function at the service switching point 13 need not be modified. Instead, all modifications can be made at the service control point 14.
Essentially, the only customization of the service switching point 13 is programming that allows it to recognize intelligent network triggers (call numbers assigned to intelligent network services) so it can request switching information from the service control point 14 when the triggers are detected. Otherwise, the service switching point 13 operates in accordance with ordinary exchange functions. The service switching point 13 thus must take care of both the handling of calls from the caller 12 to the transit exchange 16 as well as operations signals to the service control point 14.
The service control function (SCF) at the service control point 14, provides a foundation in which new services can be introduced to the system quickly. The framework operates around a service script interpreter which interprets newly introduced service scripts identifying the new services to be provided by the network. As discussed above, the service control function (SCF) is invoked by a trigger sensed at the service switching point 13. Upon receipt of the triggering function, the service control point 14 starts the script interpretation operation based on the type of trigger received. The operation will result in some outcome, which provides an instruction for handling the call switching associated with the trigger event.
The service script, which operates at the service control point 14, is a combination of service logic and service data. The service logic is made up of a number of modules that allow new services to be introduced easily and be modified easily once introduced. These modules are referred to previously as the service independent building blocks (SIB""s). An example architectural embodiment of such and SCP using SIB""s is shown in FIG. 9.
Intelligent networking, such as is described with respect to FIG. 1, is thus an architectural concept that aims to ease the introduction of new services.
Due to customer demand, intelligent networking in the wireless environment is commercially required. Wireless intelligent networking, like land-based intelligent networking, is an architectural concept that aims to ease the introduction of new services in the wireless environment. Ideally, wireless intelligent networking provides support for both standard phone mobility (such as, for example, the IS 41 protocol in traditional cellular networks), together with intelligent network concepts. Wireless intelligent networking resolves numerous problems associated with the cellular network. First, intelligent networking in the wireless environment reduces the time required to develop and deploy new services. Second, it frees the service providers up to provide custom designed services, without dependency upon the switch suppliers for development and implementation of the services into the switch function. Third, with intelligent networking in the wireless environment, wireless network service providers can differentiate their services from competitive offerings. The present invention provides several options for functionally layering the wireless network to accommodate wireless intelligent networking.